NUCLEONIX SYSTEMS RC 705E Instruction Manual page 33

12Q) Can we have some conversions between Sv & R ?
1 Sv/hr = 100 R/hr
1 mSv = 100 mR/hr
1µSv = 100 µR/hr
10 nSv = 1 ?R/hr
10 µSv/hr = 1000 µR/hr
= 100 mR/hr
0.1 µSv/hr = 10 µR/hr
13Q) What is Becquerel (Bq)?
SI unit of activity. It is define as no. of radioactive transformations or isomeric transitions per second = 1 Bq.
It defines the source 'activity' or 'strength'
14Q) What are the clearance levels radioactive contamination in European countries, UK & USA?
Allowable Limits for Radioactive Contamination Analyzer in steel in different countries are given below.USA
it is nil.
European Union
Germany
U.K
Japan
IAEA (BSS)
For Material upto one tones IAEA =
For bulk material without limit ICRP=
However it may be good practice to observe the limit as <0.1 Bq / gm
15Q) What is Natural background radiation?
A) In the nature exists background radiation, due to geo-structure, terrain, rocks, cosmic radiation flooring, tiles,
walls etc. also contribute to background radiation levels. Natural background varies from place to place and
could be in the range of (3-4) µR/h to (30-40) µR/h. (0.03µSv/h to 0.4µSv/h). At a single location also,
natural background varies and this is called statistical variation. For practical purposes, we take the highest
observed reading in a location as natural background.
Rad check meter is an instrument which measures radiation dose rates from natural background radiation
levels onwards. Its sensitivity is typically 1 µR/hr or 0.01 µSv /hr.
16Q) Is natural background level different at different places?
A) Yes, it is different in different cities & places, for e.g. in Hyderabad, India it is more, it is approx 30 µR /hr. In
Mumbai, India it is approx (6 to 8) µR/hr. (About FIVE times less than that in Hyderabad).
17Q) Whether contamination reading as shown in the display will be same in different places for the same sample
under same measurement condition?
A) No, unless the background level is same at two different places where you would have made measurement,
meter reading will be different for the same contamination levels. This is because the background at these
two places may be different.
Please note that natural background levels get added up to the meter reading along with reading due to sample
contamination, i.e.,
Meter reading = Sample contamination + Natural Background
However if you account for reading due to background, then reading due to sample will be same, inthe different
places.
= 1.0 Bq/gm
= 0.1 Bq/gm
= 0.4 Bq/gm
= 1.0 Bq/gm
= 1.0 Bq/gm
0.1 Bq/g
0.1 Bq/ gm
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